scholarly journals Development of an Enzyme-Linked Immunosorbent Assay Using a Recombinant LigA Fragment Comprising Repeat Domains 4 to 7.5 as an Antigen for Diagnosis of Equine Leptospirosis

2013 ◽  
Vol 20 (8) ◽  
pp. 1143-1149 ◽  
Author(s):  
Weiwei Yan ◽  
Muhammad Hassan Saleem ◽  
Patrick McDonough ◽  
Sean P. McDonough ◽  
Thomas J. Divers ◽  
...  

ABSTRACTLeptospiraimmunoglobulin (Ig)-like (Lig) proteins are a novel family of surface-associated proteins in which the N-terminal 630 amino acids are conserved. In this study, we truncated the LigA conserved region into 7 fragments comprising the 1st to 3rd (LigACon1-3), 4th to 7.5th (LigACon4-7.5), 4th (LigACon4), 4.5th to 5.5th (LigACon4.5–5.5), 5.5th to 6.5th (LigACon5.5–6.5), 4th to 5th (LigACon4-5), and 6th to 7.5th (LigACon6-7.5) repeat domains. All 7 recombinant Lig proteins were screened using a slot-shaped dot blot assay for the diagnosis of equine leptospirosis. Our results showed that LigACon4-7.5 is the best candidate diagnostic antigen in a slot-shaped dot blot assay. LigACon4-7.5 was further evaluated as an indirect enzyme-linked immunosorbent assay (ELISA) antigen for the detection ofLeptospiraantibodies in equine sera. This assay was evaluated with equine sera (n= 60) that were microscopic agglutination test (MAT) negative and sera (n= 220) that were MAT positive to the 5 serovars that most commonly cause equine leptospirosis. The indirect ELISA results showed that at a single serum dilution of 1:250, the sensitivity and specificity of ELISA were 80.0% and 87.2%, respectively, compared to those of MAT. In conclusion, an indirect ELISA was developed utilizing a recombinant LigA fragment comprising the 4th to 7.5th repeat domain (LigACon4-7.5) as a diagnostic antigen for equine leptospirosis. This ELISA was found to be sensitive and specific, and it yielded results that concurred with those of the standard MAT.

2011 ◽  
Vol 24 (1) ◽  
pp. 42-50 ◽  
Author(s):  
Ming Yang ◽  
Rebekah van Bruggen ◽  
Wanhong Xu

Seneca Valley virus (SVV), a member of the Picornaviridae family, was implicated in a suspicious vesicular disease discovered in pigs from Canada in 2007. Because any outbreak of vesicular disease in pigs is assumed to be foot-and-mouth disease (FMD) until confirmed otherwise, a test for diagnosing the presence of SVV would be a very useful tool. To develop the diagnostic tests for SVV infection, 5 monoclonal antibodies (mAbs) were produced from mice immunized with binary ethylenimine (BEI)-inactivated SVV. Using a dot blot assay, the reactivity of the mAbs was confirmed to be specific for SVV, not reacting with any of the other vesicular disease viruses tested. The mAbs demonstrated reactivity with SVV antigen in infected cells by an immunohistochemistry assay. An SVV-specific competitive enzyme-linked immunosorbent assay (cELISA) was developed using BEI-inactivated SVV antigen and a mAb for serodiagnosis. The cELISA results were compared to the indirect isotype (immunoglobulin [Ig]M and IgG) ELISA and the virus neutralization test. All SVV experimentally inoculated pigs exhibited a positive SVV-specific antibody response at 6 days postinoculation, and the sera remained positive until the end of the experiment on day 57 (>40% inhibition) using the cELISA. The cELISA reflected the profile of the indirect ELISA for both IgM and IgG. This panel of SVV-specific mAbs is valuable for the identification of SVV antigen and the serological detection of SVV-specific antibodies.


2013 ◽  
Vol 20 (9) ◽  
pp. 1410-1417 ◽  
Author(s):  
Ting Xin ◽  
Hongjun Yang ◽  
Nan Wang ◽  
Fang Wang ◽  
Peng Zhao ◽  
...  

ABSTRACTBrucellosis is a serious zoonosis that occurs worldwide, and its diagnosis is typically based on the detection of antibodies againstBrucellalipopolysaccharide (LPS). However, the specificity of the LPS-based test is compromised by cross-reactivity withEscherichia coliO157:H7 andYersinia enterocoliticaO:9. Also, diagnosis based on the LPS test cannot differentiate between vaccinated and infected individuals. The detection of the 26-kDa cytosoluble protein (BP26) antibody is considered an alternative that circumvents these drawbacks because it is exclusively expressed by infectiousBrucella. A BP26-based enzyme-linked immunosorbent assay (ELISA) has been tried for the diagnosis ofBrucella-infected animals and humans, but a few results showed that BP26 couldn't react with allBrucella-positive sera. In order to explore whether different animals could produce antibodies against BP26 after being infected with variousBrucellaspecies, we infected sheep, goats, and beef cattle with common virulent referenceBrucellaspecies. All sera were collected from the experimental animals and tested using both LPS-based ELISAs and BP26-based ELISAs. The results showed that allBrucella-infected individuals could produce high levels of antibodies against LPS, but onlyB. melitensis16M- andB. melitensisM28-infected sheep andB. melitensis16M- andB. abortus2308-infected goats could produce antibodies against BP26. Therefore, we concluded that the BP26-based indirect ELISA (i-ELISA) showed bothBrucellaspecies and host specificity, which obviously limits its reliability as a substitute for the traditional LPS-based ELISA for the detection of brucellosis.


2008 ◽  
Vol 56 (1) ◽  
pp. 10-14 ◽  
Author(s):  
I. Bargou ◽  
A. Mankaï ◽  
A. Jamaa ◽  
I. Ben Jazia ◽  
K. Skandrani ◽  
...  

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Joel D. Ernst ◽  
Amber Cornelius ◽  
Miriam Bolz

ABSTRACTSecretion of specific proteins contributes to pathogenesis and immune responses in tuberculosis and other bacterial infections, yet the kinetics of protein secretion and fate of secreted proteinsin vivoare poorly understood. We generated new monoclonal antibodies that recognize theMycobacteriumtuberculosissecreted protein Ag85B and used them to establish and characterize a sensitive enzyme-linked immunosorbent assay (ELISA) to quantitate Ag85B in samples generatedin vitroandin vivo. We found that nutritional or culture conditions had little impact on the secretion of Ag85B and that there is considerable variation in Ag85B secretion by distinct strains in theM. tuberculosiscomplex: compared with the commonly used H37Rv strain (lineage 4),Mycobacteriumafricanum(lineage 6) secretes less Ag85B, and two strains from lineage 2 secrete more Ag85B. We also used the ELISA to determine that the rate of secretion of Ag85B is 10- to 100-fold lower than that of proteins secreted by Gram-negative and Gram-positive bacteria, respectively. ELISA quantitation of Ag85B in lung homogenates ofM. tuberculosisH37Rv-infected mice revealed that although Ag85B accumulates in the lungs as the bacterial population expands, the amount of Ag85B per bacterium decreases nearly 10,000-fold at later stages of infection, coincident with the development of T cell responses and arrest of bacterial population growth. These results indicate that bacterial protein secretionin vivois dynamic and regulated, and quantitation of secreted bacterial proteins can contribute to the understanding of pathogenesis and immunity in tuberculosis and other infections.IMPORTANCEBacterial protein secretion contributes to host-pathogen interactions, yet the process and consequences of bacterial protein secretion during infection are poorly understood. We developed a sensitive ELISA to quantitate a protein (termed Ag85B) secreted byM. tuberculosisand used it to find that Ag85B secretion occurs with slower kinetics than for proteins secreted by Gram-positive and Gram-negative bacteria and that accumulation of Ag85B in the lungs is markedly regulated as a function of the bacterial population density. Our results demonstrate that quantitation of bacterial proteins during infection can reveal novel insights into host-pathogen interactions.


2018 ◽  
Vol 50 (3) ◽  
pp. 229-235 ◽  
Author(s):  
Suresh Bokoliya ◽  
Shripad Patil ◽  
Madhu Nagappa ◽  
Arun Taly

AbstractObjectiveTo assess the practicality of dot-blot testing for rapid and sensitive detection of the antiacetylcholine receptor (anti-AChR) antibodies in myasthenia gravis (MG).MethodsIn this case-control study, we tested serum specimens of 85 patients with MG, 85 healthy control individuals, and 85 patients without MG who have other autoimmune and neurological illnesses. All the serum specimens were tested for anti-AChR antibodies using 3 assays: in-house enzyme-linked immunosorbent assay (ELISA), the dot-blot assay, and commercial ELISA.ResultsIn-house ELISA, commercial ELISA, and dot-blot test results were positive for anti-AChR antibodies in 65 (76.5%) patients with MG. The results of all 3 tests were negative for anti-AChR antibodies in healthy controls and patients without MG. We observed perfect concordance (K = 1, P <.001) between all 3 tests. In-house ELISA correlated significantly (r = 0.873, P <.001) with commercial ELISA. In-house ELISA and the dot-blot test demonstrated similar diagnostic performance in detecting anti-AChR antibodies.ConclusionsThe dot-blot assay is a simple, nonradioactive immune assay for rapid detection of anti-AChR antibodies in MG.


1987 ◽  
Vol 70 (4) ◽  
pp. 657-661
Author(s):  
Titan S L Fan ◽  
Yi-Chun Xu ◽  
Fun Sun Chu

Abstract An indirect enzyme-linked immunosorbent assay (ELISA) for the detection of HT-2 toxin in the presence or absence of T-2 toxin is described. In the indirect ELISA, the relative cross-reactivities of antibodies against T-2 toxin (anti-T-2) with T-2 toxin and HT-2 toxin were 1 and 0.1, whereas anti-HT-2 cross-reactivities with T-2 toxin and HT-2 toxin were 0.33 and 1, respectively. Using such relationships, a formula was established that could be used to calculate the individual toxin concentration in a mixed sample after experimentally analyzing for T-2 and HT-2 toxins in the 2 indirect ELISAs. This method was tested by analyzing urine samples spiked with HT-2 toxin alone and samples spiked with both T-2 toxin and HT-2 toxin. A cleanup protocol for treatment of urine samples before ELISA was also established. The overall analytical recovery of HT-2 toxin when it was added at concentrations of 0.1-10 parts per billion (ppb) to the urine samples was ca 89%. When both T-2 and HT-2 toxins were added to the urine samples at equal concentrations of 0.5 to 5.0 ppb, their recoveries were 112 and 109%, respectively.


2016 ◽  
Vol 54 (6) ◽  
pp. 1557-1565 ◽  
Author(s):  
Martin Heller ◽  
Nimmo Gicheru ◽  
Georgina Tjipura-Zaire ◽  
Cecilia Muriuki ◽  
Mingyan Yu ◽  
...  

Contagious bovine pleuropneumonia (CBPP) is a severe respiratory disease that is widespread in sub-Saharan Africa. It is caused byMycoplasma mycoidessubsp.mycoides, a bacterium belonging to theMycoplasma mycoidescluster. In the absence of an efficient CBPP vaccine, improved and easy-to-use diagnostic assays for recurrent testing combined with isolation and treatment of positive animals represent an option for CBPP control in Africa. Here we describe the comprehensive screening of 17 immunogenicMycoplasma mycoidessubsp.mycoidesproteins using well-characterized bovine sera for the development of a novel cocktail enzyme-linked immunosorbent assay (ELISA) for laboratory use. Two recombinantMycoplasmaimmunogens, MSC_0136 and MSC_0636, were used to set up a standardized cocktail ELISA protocol. According to the results from more than 100 serum samples tested, the sensitivity and specificity of the novel cocktail ELISA were 85.6% and 96.4%, respectively, with an overall diagnostic accuracy comparable to that of the Office International des Epizooties (OIE)-prescribed serological assays. In addition, we provide a proof of principle for a field-applicable, easy-to-use commercially produced prototype lateral-flow test for rapid (<30-min) diagnosis of CBPP.


2000 ◽  
Vol 7 (6) ◽  
pp. 977-979 ◽  
Author(s):  
Kritsana Janyapoon ◽  
Sunee Korbsrisate ◽  
Hatairat Thamapa ◽  
Sittichai Thongmin ◽  
Suwattana Kanjanahareutai ◽  
...  

ABSTRACT A dot blot enzyme-linked immunosorbent assay (ELISA) with a monoclonal antibody specific to phase1-c Salmonella was developed for the direct detection of Salmonella entericaserovar Choleraesuis in blood cultures. This system was applied to the identification of serovar Choleraesuis, and the results were compared with those obtained by a conventional biochemical method. It was revealed that all 12 samples identified to be infected with serovar Choleraesuis were positive on testing by the ELISA. In contrast, 77 samples infected with bacteria commonly isolated from the blood were not reactive by the ELISA. The calculated sensitivity and specificity of the established assay are 100%.


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